How to update custom multi-user field in Zoho Projects?

How to update custom multi-user field in Zoho Projects?

I'm trying to update custom multi-user fields in Zoho Projects via a Deluge function in CRM.

The code I have so far is below. It works for updating standard project fields and single-line custom fields, but it does not work to update multi-user fields. I assume the problem is the format I'm passing the multi-user data in. 

I've been looking for answers and found two sources for multi-user fields in Projects. The first: https://www.zoho.com/projects/help/rest-api/projects-api.html#update-project seems to contradict the second: https://projects.zoho.com/api-docs#field-types

I'd love some help!


  1. void automation.updateProjectExample()
  2. {
  3.     // Get custom fields for the portal
  4.     fieldsResponse = invokeurl
  5.     [
  6.         url: "https://projectsapi.zohocloud.ca/restapi/portal/your_portal_name/projects/customfields/"
  7.         type: GET
  8.         connection: "your_connection_name"
  9.     ];
  10.     info fieldsResponse;

  12.     // Map field names to field IDs
  13.     fieldMap = map();
  14.     for each field in fieldsResponse.get("project_custom_fields")
  15.     {
  16.         fieldName = field.get("field_name");
  17.         fieldID = field.get("field_id");
  18.         fieldMap.put(fieldName, fieldID);
  19.     }
  20.     info fieldMap;

  22.     // Get related instructors from a CRM deal
  23.     dealId = 1234567890;  // Example Deal ID
  24.     deal = zoho.crm.getRecordById("Deals", dealId);
  25.     dealName = deal.get("Deal_Name");
  26.     projectId = 9876543210; // Example Project ID

  28.     instructors = zoho.crm.getRelatedRecords("Instructors", "Deals", dealId);

  30.     instructorOneUsers = list();
  31.     instructorTwoUsers = list();
  32.     customizerUsers = list();

  34.     // Organize users by role
  35.     for each instructor in instructors
  36.     {
  37.         role = instructor.get("Role");
  38.         zpuid = instructor.get("Zoho_Projects_user_ID"); // The instructor's Zoho Projects user id is stored in this field 

  40.         if(role == "Instructor one")
  41.         {
  42.             instructorOneUsers.add(zpuid);
  43.         }
  44.         else if(role == "Instructor two")
  45.         {
  46.             instructorTwoUsers.add(zpuid);
  47.         }
  48.         else if(role == "Customizer")
  49.         {
  50.             customizerUsers.add(zpuid);
  51.         }
  52.     }

  54.     // Build payload for updating the project. Updating these standard fields works. 
  55.     payload = Map();
  56.     payload.put("description", "Updated via Deluge script");
  57.     payload.put("start_date","11-01-2025");
  58.     payload.put("end_date","11-01-2026");

  60.     // Example of updating a single-line custom field. This works.
  61.     payload.put("UDF_CHAR20", "Sample text for testing");

  63.     // Example of updating a multi-user custom field (Instructor One). This does not work.
  64.     payload.put("UDF_MULTIUSER1", "4320000000540073"); // Replace with actual user IDs

  66.     // Make the API call to update the project
  67.     resp = invokeurl
  68.     [
  69.         url: "https://projectsapi.zohocloud.ca/restapi/portal/your_portal_name/projects/" + projectId + "/"
  70.         type: POST
  71.         parameters: payload
  72.         connection: "your_connection_name"
  73.     ];

  75.     info resp;
  76. }






    • Sticky Posts

    • Update on V2 API End-of-Life Timeline

      Dear Users, Earlier this year, we shared the launch of the V3 APIs and requested users to migrate from the older V2 APIs by December 2025. We have received valuable feedback from our users and partners regarding their migration timelines. We are happy

    • Automation Series: Auto-assign Task Followers

      As task progresses, several users are required to stay aware of the updates to plan their upcoming work items efficiently. Manually adding users as followers for an active task might create additional overhead. With this automation, followers can be added

    • WhatsApp Business Integration for Zoho Projects

      Delivery channel plays a decisive role in how quickly certain project updates translate into immediate actions. A release is ready to go live. An issue is marked critical. An approval is pending. These moments are less about tracking and more about timely

    • Enhanced Collaboration and Global Web Tabs

      Hello Users, We are rolling out two key enhancements in Zoho Projects that will be part of our November release. Here’s what to expect: 1. Collaboration Section in the Left Navigation Panel What’s new? All communication and interactive tools will be grouped

    • Choosing the Right Automation in Zoho Projects

      In any project, different types of actions are needed at different points. Some projects require control on how tasks move, some require reacting to updates, and some require executing additional actions beyond the task. Automation in Zoho Projects is